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Commit dab44f5

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Merge pull request youngyangyang04#1329 from wzqwtt/patch10
添加(0344.反转字符串、0541.反转字符串II、剑指Offer05.替换空格)Scala版本
2 parents 83726ac + 037bebb commit dab44f5

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‎problems/0344.反转字符串.md‎

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Original file line numberDiff line numberDiff line change
@@ -266,6 +266,20 @@ public class Solution
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}
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}
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```
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Scala:
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```scala
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object Solution {
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def reverseString(s: Array[Char]): Unit = {
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var (left, right) = (0, s.length - 1)
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while (left < right) {
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var tmp = s(left)
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s(left) = s(right)
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s(right) = tmp
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left += 1
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right -= 1
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}
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}
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}
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```
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<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

‎problems/0541.反转字符串II.md‎

Lines changed: 42 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -347,6 +347,47 @@ public class Solution
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}
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}
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```
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Scala:
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版本一: (正常解法)
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```scala
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object Solution {
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def reverseStr(s: String, k: Int): String = {
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val res = s.toCharArray // 转换为Array好处理
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for (i <- s.indices by 2 * k) {
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// 如果i+k大于了res的长度,则需要全部翻转
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if (i + k > res.length) {
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reverse(res, i, s.length - 1)
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} else {
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reverse(res, i, i + k - 1)
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}
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}
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new String(res)
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}
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// 翻转字符串,从start到end
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def reverse(s: Array[Char], start: Int, end: Int): Unit = {
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var (left, right) = (start, end)
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while (left < right) {
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var tmp = s(left)
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s(left) = s(right)
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s(right) = tmp
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left += 1
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right -= 1
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}
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}
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}
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```
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版本二: 首先利用sliding每隔k个进行分割,随后转换为数组,再使用zipWithIndex添加每个数组的索引,紧接着利用map做变换,如果索引%2==0则说明需要翻转,否则原封不动,最后再转换为String
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```scala
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object Solution {
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def reverseStr(s: String, k: Int): String = {
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s.sliding(k, k)
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.toArray
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.zipWithIndex
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.map(v => if (v._2 % 2 == 0) v._1.reverse else v._1)
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.mkString
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}
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}
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```
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<div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>

‎problems/剑指Offer05.替换空格.md‎

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Original file line numberDiff line numberDiff line change
@@ -413,8 +413,62 @@ func replaceSpace(_ s: String) -> String {
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}
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```
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Scala:
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方式一: 双指针
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```scala
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object Solution {
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def replaceSpace(s: String): String = {
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var count = 0
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s.foreach(c => if (c == ' ') count += 1) // 统计空格的数量
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val sOldSize = s.length // 旧数组字符串长度
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val sNewSize = s.length + count * 2 // 新数组字符串长度
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val res = new Array[Char](sNewSize) // 新数组
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var index = sNewSize - 1 // 新数组索引
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// 逆序遍历
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for (i <- (0 until sOldSize).reverse) {
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if (s(i) == ' ') {
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res(index) = '0'
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index -= 1
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res(index) = '2'
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index -= 1
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res(index) = '%'
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} else {
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res(index) = s(i)
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}
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index -= 1
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}
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res.mkString
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}
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}
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```
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方式二: 使用一个集合,遇到空格就添加%20
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```scala
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object Solution {
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import scala.collection.mutable.ListBuffer
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def replaceSpace(s: String): String = {
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val res: ListBuffer[Char] = ListBuffer[Char]()
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for (i <- s.indices) {
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if (s(i) == ' ') {
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res += '%'
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res += '2'
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res += '0'
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}else{
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res += s(i)
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}
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}
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res.mkString
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}
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}
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```
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方式三: 使用map
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```scala
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object Solution {
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def replaceSpace(s: String): String = {
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s.map(c => if(c == ' ') "%20" else c).mkString
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}
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}
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```
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